Integrated circuit reliability testing

A technique is described for use in determining the reliability of microscopic conductors deposited on an uneven surface of an integrated circuit device. A wafer containing integrated circuit chips is formed with a test area having regions of different heights. At the time the conductors are formed on the chip areas of the wafer, an elongated serpentine assay conductor is deposited on the test area so the assay conductor extends over multiple steps between regions of different heights. Also, a first test conductor is deposited in the test area upon a uniform region of first height, and a second test conductor is deposited in the test area upon a uniform region of second height. The occurrence of high resistances at the steps between regions of different height is indicated by deriving the measured length of the serpentine conductor using the resistance measured between the ends of the serpentine conductor, and comparing that to the design length of the serpentine conductor. The percentage by which the measured length exceeds the design length, at which the integrated circuit will be discarded, depends on the required reliability of the integrated circuit

Continuous-Time Formulations for Multi-Mode Project Scheduling

This paper reviews compact continuous-time formulations for the multi-mode resource-constrained project scheduling problem. Specifically, we first point out a serious flaw in an existing start-end-event-based formulation owing to inconsistent mode choices. We propose two options to formulate the missing constraints and we consider an equivalent reformulation with sparser constraint matrix. Second, we formulate an aggregate variant of an existing model that relies on on-off-events and clarify the role of mode consistency issues in such models. Third, we suggest two variants of an existing network flow formulation. We enhance our models by adapting several techniques that have been used previously, e.g., in cases with only a single mode. A large set of benchmark instances from the literature provides the basis for an up-to-date and fair computational study with an out-of-the-box solver package. We compare our models against two models from the literature. Our experiments assert confidently that network flow formulations prevail in the test bed, and they provide a hint on why event-based models become less competitive in multi-mode settings.Comment: 37 page

Attractor reconstruction of an impact oscillator for parameter identification

Peer reviewedPreprin

Counterparty Credit Risk in OTC Derivatives under Basel III

International audienceRecent financial crises were the root of many changes in regulatory implementations in the banking sector. Basel previously covered the default capital charge for counterparty exposures however, the crisis showed that more than two third of the losses related to this risk emerged from the exposure to the movement of the counterparty's credit quality and not its actual default therefore, Basel III divided the required counterparty risk capital into two categories: The traditional default capital charge and an additional counter-party credit valuation adjustment (CVA) capital charge. In this article, we explain the new methodologies to compute these capital charges on the OTC market: The standardized approach for default capital charge (SA-CCR) and the basic approach for CVA (BA-CVA). Based on historical calibration and future estimations, we built internal models in order to compare them with the amended standardized approach. Up till June 2015, interest rate and FX derivatives constituted more than 90% of the traded total OTC notional amount; we constructed our application on such portfolios containing and computed their total counterparty capital charge. The analysis reflected different impacts of the netting and collateral agreements on the regulatory capital depending on the instruments' typologies. Moreover, results showed an important increase in the capital charge due to the CVA addition doubling it in some cases

The Suggested Activities for Use in the Development of a Curriculum Guide for the Educable Mentally Retarded at the Primary, Intermediate, and Secondary Levels

It is the purpose of this study to suggest activities for use in a curriculum guide for the educable mentally retarded in physical education at the primary, intermediate, and secondary levels

Ocular rigidity : a previously unexplored risk factor in the pathophysiology of open-angle glaucoma : assessment using a novel OCT-based measurement method

Le glaucome est la première cause de cécité irréversible dans le monde. Bien que sa pathogenèse demeure encore nébuleuse, les propriétés biomécaniques de l’oeil sembleraient jouer un rôle important dans le développement et la progression de cette maladie. Il est stipulé que la rigidité oculaire (RO) est altérée au travers les divers stades de la maladie et qu’elle serait le facteur le plus influent sur la réponse du nerf optique aux variations de la pression intraoculaire (PIO) au sein du glaucome. Pour permettre l’investigation du rôle de la RO dans le glaucome primaire à angle ouvert (GPAO), la capacité de quantifier la RO in vivo par l’entremise d’une méthode fiable et non-invasive est essentielle. Une telle méthode n’est disponible que depuis 2015. Basée sur l'équation de Friedenwald, cette approche combine l'imagerie par tomographie par cohérence optique (TCO) et la segmentation choroïdienne automatisée afin de mesurer le changement de volume choroïdien pulsatile (ΔV), ainsi que la tonométrie dynamique de contour Pascal pour mesurer le changement de pression pulsatile correspondant. L’objectif de cette thèse est d’évaluer la validité de cette méthode, et d’en faire usage afin d’investiguer le rôle de la RO dans les maladies oculaires, particulièrement le GPAO. Plus spécifiquement, cette thèse vise à : 1) améliorer la méthode proposée et évaluer sa validité ainsi que sa répétabilité, 2) investiguer l’association entre la RO et le dommage neuro-rétinien chez les patients glaucomateux, et ceux atteints d’un syndrome de vasospasticité, 3) évaluer l’association entre la RO et les paramètres biomécaniques de la cornée, 4) évaluer l’association entre la RO et les pics de PIO survenant suite aux thérapies par injections intravitréennes (IIV), afin de les prédire et de les prévenir chez les patients à haut risque, et 5) confirmer que la RO est réduite dans les yeux myopes. D’abord, nous avons amélioré le modèle mathématique de l’oeil utilisé pour dériver ΔV en le rendant plus précis anatomiquement et en tenant compte de la choroïde périphérique. Nous avons démontré la validité et la bonne répétabilité de cette méthodologie. Puis, nous avons effectué la mesure des coefficients de RO sur un large éventail de sujets sains et glaucomateux en utilisant notre méthode non-invasive, et avons démontré, pour la première fois, qu'une RO basse est corrélée aux dommages glaucomateux. Les corrélations observées étaient comparables à celles obtenues avec des facteurs de risque reconnus tels que la PIO maximale. Une forte corrélation entre la RO et les dommages neuro-rétiniens a été observée chez les patients vasospastiques, mais pas chez ceux atteints d'une maladie vasculaire ischémique. Cela pourrait potentiellement indiquer une plus grande susceptibilité au glaucome due à la biomécanique oculaire chez les patients vasospastiques. Bien que les paramètres biomécaniques cornéens aient été largement adoptés dans la pratique clinique en tant que substitut pour la RO, propriété biomécanique globale de l'oeil, nous avons démontré une association limitée entre la RO et ces paramètres, offrant une nouvelle perspective sur la relation entre les propriétés biomécaniques cornéennes et globales de l’oeil. Seule une faible corrélation entre le facteur de résistance cornéenne et la RO demeure après ajustement pour les facteurs de confusion dans le groupe des patients glaucomateux. Ensuite, nous avons présenté un modèle pour prédire l'amplitude des pics de PIO après IIV à partir de la mesure non-invasive de la RO. Ceci est particulièrement utile pour les patients à haut risque atteints de maladies rétiniennes exsudatives et de glaucome qui nécessiteraient des IIV thérapeutiques, et pourrait permettre aux cliniciens d'ajuster ou de personnaliser le traitement pour éviter toute perte de vision additionnelle. Enfin, nous avons étudié les différences de RO entre les yeux myopes et les non-myopes en utilisant cette technique, et avons démontré une RO inférieure dans la myopie axiale, facteur de risque du GPAO. Dans l'ensemble, ces résultats contribuent à l’avancement des connaissances sur la physiopathologie du GPAO. Le développement de notre méthode permettra non seulement de mieux explorer le rôle de la RO dans les maladies oculaires, mais contribuera également à élucider les mécanismes et développer de nouveaux traitements ciblant la RO pour contrer la déficience visuelle liée à ces maladies.Glaucoma is the leading cause of irreversible blindness worldwide. While its pathogenesis is yet to be fully understood, the biomechanical properties of the eye are thought to be involved in the development and progression of this disease. Ocular rigidity (OR) is thought to be altered through disease processes and has been suggested to be the most influential factor on the optic nerve head’s response to variations in intraocular pressure (IOP) in glaucoma. To further investigate the role of OR in open-angle glaucoma (OAG) and other ocular diseases such as myopia, the ability to quantify OR in living human eyes using a reliable and non-invasive method is essential. Such a method has only become available in 2015. Based on the Friedenwald equation, the method uses time-lapse optical coherence tomography (OCT) imaging and automated choroidal segmentation to measure the pulsatile choroidal volume change (ΔV), and Pascal dynamic contour tonometry to measure the corresponding pulsatile pressure change. The purpose of this thesis work was to assess the validity of the methodology, then use it to investigate the role of OR in ocular diseases, particularly in OAG. More specifically, the objectives were: 1) To improve the extrapolation of ΔV and evaluate the method’s validity and repeatability, 2) To investigate the association between OR and neuro-retinal damage in glaucomatous patients, as well as those with concomitant vasospasticity, 3) To evaluate the association between OR and corneal biomechanical parameters, 4) To assess the association between OR and IOP spikes following therapeutic intravitreal injections (IVIs), to predict and prevent them in high-risk patients, and 5) To confirm that OR is lower in myopia. First, we improved the mathematical model of the eye used to derive ΔV by rendering it more anatomically accurate and accounting for the peripheral choroid. We also confirmed the validity and good repeatability of the method. We carried out the measurement of OR coefficients on a wide range of healthy and glaucomatous subjects using this non-invasive method, and were able to show, for the first time, that lower OR is correlated with more glaucomatous damage. The correlations observed were comparable to those obtained with recognized risk factors such as maximum IOP. A strong correlation between OR and neuro-retinal damage was found in patients with concurrent vasospastic syndrome, but not in those with ischemic vascular disease. This could perhaps indicate a greater susceptibility to glaucoma due to ocular biomechanics in vasospastic patients. While corneal biomechanical parameters have been widely adopted in clinical practice as surrogate measurements for the eye’s overall biomechanical properties represented by OR, we have shown a limited association between these parameters, bringing new insight unto the relationship between corneal and global biomechanical properties. Only a weak correlation between the corneal resistance factor and OR remained in glaucomatous eyes after adjusting for confounding factors. In addition, we presented a model to predict the magnitude of IOP spikes following IVIs from the non-invasive measurement of OR. This is particularly useful for high-risk patients with exudative retinal diseases and glaucoma that require therapeutic IVIs, and could provide the clinician an opportunity to adjust or customize treatment to prevent further vision loss. Finally, we investigated OR differences between non-myopic and myopic eyes using this technique, and demonstrated lower OR in axial myopia, a risk factor for OAG. Overall, these findings provide new insights unto the pathophysiology of glaucomatous optic neuropathy. The development of our method will permit further investigation of the role of OR in ocular diseases, contributing to elucidate mechanisms and provide novel management options to counter vision impairment caused by these diseases

Effects of sirtuin 1 on arterial stiffening in a model of diet-induced obesity

BACKGROUND: Arterial stiffness, or the loss of compliance of the large arteries, is a major independent predictor of cardiovascular events. Obesity induced by a high fat, high sucrose (HFHS) diet, in mice, causes the development of arterial stiffness, diabetes, and hypertension. Along with the resulting metabolic syndrome, inflammation and oxidants are increased in vascular smooth muscle (VSM) cells of HFHS-fed mice. Sirtuin 1 (SirT1), an important cellular homeostatic regulator, has been shown to prevent inflammation and obesity-associated metabolic impairment in animal models. This deacetylase is involved in histone and transcription factor regulation, thereby affecting a wide range of physiological mechanisms. However, whether SirT1 affects obesity-induced arterial stiffness is unknown. Therefore, we aimed to investigate the effects of SirT1 on arterial stiffening in a setting of diet-induced obesity. METHODS: The polyphenolic SirT1 activators, resveratrol and S17834, were added to HFHS diet fed to WT mice for 8 months. Arterial stiffness was measured in vivo, by pulse wave velocity (PWV), at baseline, 4 months, and 8 months. In another experiment, a highly selective SirT1 activator, SRT1720, was administered to mice in HFHS diet for one week following 8 months of HFHS diet, and PWV was measured before and after treatment. To study the role of VSM SirT1 in HFHS-induced arterial stiffness, resveratrol was supplemented to HFHS diet-fed mice lacking SirT1 in VSM (SMKO), and PWV was measured in comparison to control HFHS-fed mice. Additionally, mice overexpressing SirT1 in VSM specifically (SMTG) were generated and placed on HFHS diet, and PWV was measured at baseline, 4 months, and 8 months. The effects of SirT1 on oxidant production and inflammation in the different experimental groups were assessed by staining aortic sections for oxidants and performing Western blots of inflammatory markers (phospho-p65 NFκB, VCAM1) on isolated aortic and VSM cell lysates. RESULTS: Administering resveratrol and S17834 completely prevented the development HFHS-induced arterial stiffness over 8 months. Similarly, elevated PWV due to 8 months of HFHS diet was reversed by one-week treatment with SRT1720. SirT1 knockout in VSM partially prevented resveratrol’s effect in lowering arterial stiffness. Mice overexpressing SirT1 in VSM (SMTG) did not develop arterial stiffness and were protected from HFHS-induced oxidant production and inflammation (upregulation of phospho-p65 NFκB and VCAM1). CONCLUSIONS: VSM SirT1 can prevent the development of arterial stiffness in settings of obesity by opposing oxidants and inflammation in the aortic wall. SirT1 activators represent a potential therapeutic approach to alleviate the burden of cardiovascular disease in obese individuals with metabolic syndrome.2018-06-16T00:00:00